[dart:io] Move Platform.ansiSupported to {Stdin,Stdout}.supportsAnsiEscapes

runtime/bin/platform_unsupported.cc

Index: runtime/bin/platform_unsupported.cc
diff --git a/runtime/bin/platform_unsupported.cc b/runtime/bin/platform_unsupported.cc
index 520d9f2ed7b670c8815a8b89ac9dab819c84c2ad..64f62ef7e9bb63af52fa3daa49ef3ac67a847a93 100644
--- a/runtime/bin/platform_unsupported.cc
+++ b/runtime/bin/platform_unsupported.cc
@@ -64,12 +64,6 @@ void FUNCTION_NAME(Platform_GetVersion)(Dart_NativeArguments args) {
       "Platform is not supported on this platform"));
 }
 
-
-void FUNCTION_NAME(Platform_AnsiSupported)(Dart_NativeArguments args) {
-  Dart_ThrowException(DartUtils::NewInternalError(
-      "Platform is not supported on this platform"));
-}
-
 }  // namespace bin
 }  // namespace dart